JP7805885B2 - Proportional valve control device and proportional valve control method - Google Patents

Description

The present invention relates to a proportional valve control device and a proportional valve control method.

As disclosed in Patent Document 1, a conventional electromagnetic proportional valve equipped with a flow sensor that detects the flow rate of the output fluid is well known. In this electromagnetic proportional valve, the flow rate of the output fluid is monitored by the flow sensor. If the output flow rate deviates from the set value, the current applied to the electromagnetic proportional valve is increased or decreased so that the flow rate reaches the set value.

Japanese Patent Application Laid-Open No. 2004-60662

However, because the pressure at which the flow rate is used varies, the desired flow rate cannot be obtained unless a feedback circuit using a flow sensor is configured. This poses the problem of requiring a lot of labor and effort for device setup and adjustment.

The object of the present invention is to provide a proportional valve control device and proportional valve control method that can easily adjust flow rate.

a control unit that adjusts the valve opening of the valve unit by outputting a control signal corresponding to the set value to a current control circuit to control the solenoid; a pressure information input unit that inputs pressure information from at least one of a first pressure sensor that detects the pressure of the fluid flowing through an air supply port and a second pressure sensor that detects the pressure of the fluid flowing through the output port; and a temperature information input unit that inputs temperature information from a temperature sensor that detects the temperature of the fluid in either the air supply port or the output port. When setting the control signal corresponding to the set value of the flow rate of the fluid, the control unit uses the pressure information and the temperature information to determine the control signal.

A proportional valve control method for solving the above-mentioned problem is a method for controlling a balanced proportional valve in which the valve opening of a valve section is set by the suction force of a solenoid and the elastic force of an elastic section attached to the solenoid, and in which the pressures acting on the valve section and the solenoid are equal, the method comprising: acquiring a set value for fluid to be discharged from an output port; inputting pressure information from at least one of a first pressure sensor that detects the pressure of the fluid flowing through an air supply port and a second pressure sensor that detects the pressure of the fluid flowing through the output port; inputting temperature information from a temperature sensor that detects the temperature of the fluid in either the air supply port or the output port; and outputting a control signal according to the set value of the flow rate of the fluid to a current control circuit to control the solenoid, thereby determining the control signal using the pressure information and the temperature information when adjusting the valve opening of the valve section.

This invention allows for easy flow rate adjustment in proportional valves.

FIG. 2 is a cross-sectional view of the proportional valve of the first embodiment. FIG. FIG. 2 is a cross-sectional view of the proportional valve in an open state. FIG. 10 is a waveform diagram showing the change in flow rate relative to the applied current at each pressure of the fluid. FIG. 10 is a waveform diagram showing the change in effective cross-sectional area with respect to applied current. FIG. 2 is a circuit diagram of a proportional valve control device. FIG. 2 is an electrical configuration diagram of the proportional valve control device. FIG. 1 is a flow chart of fluid control. FIG. 10 is a configuration diagram of a proportional valve control device according to a second embodiment. FIG.

(First embodiment)
A first embodiment of the present disclosure will be described below.
(Overview of Proportional Valve 1)
As shown in Fig. 1, the proportional valve 1 includes a valve section 2 for switching the flow path of a fluid and a solenoid 3 for driving the valve section 2. The valve section 2 and the solenoid 3 are integrally attached by a mounting structure (not shown) using, for example, bolts or screws. The proportional valve 1 is an electromagnetic proportional valve in which the valve section 2 is electromagnetically switched between open and closed by the solenoid 3. The proportional valve 1 is a balanced type in which the pressures acting on the valve section 2 and the solenoid 3 are equal. The fluid is, for example, positive pressure air.

(Overview of Solenoid 3)
As shown in Figure 1, the solenoid 3 includes a frame 5 that forms part of the housing 4 of the proportional valve 1. The frame 5 contains a coil 6, a stator 7, and a mover 8. The coil 6 is wound around a cylindrical bobbin 9 with multiple turns. The coil 6 is shielded by a first magnetic frame 10 and a second magnetic frame 11 made of a magnetic material. The bobbin 9 has a hole 12 that extends along the axial direction of the coil 6 (the X-axis direction in Figure 1).

The first magnetic frame 10 is formed, for example, in a generally cylindrical shape with both ends open, and covers the bobbin 9 from the circumferential direction. The second magnetic frame 11 is attached to one opening 13 of the first magnetic frame 10, thereby covering the end of the bobbin 9. A seal portion 14 is attached between the bobbin 9 and the second magnetic frame 11 to seal the gap between them.

The stator 7 is inserted into the hole 12 of the bobbin 9 at a position near the base end. The threaded portion 15 (e.g., a female thread) formed on the end of the stator 7 is threaded into a threaded portion 16 (e.g., a male thread) formed on the other opening of the first magnetic frame 10. The mover 8 is inserted into both the hole 12 of the bobbin 9 and the hole 17 of the second magnetic frame 11. The tip of the mover 8 protrudes a predetermined amount from the hole 17 of the second magnetic frame 11 toward the valve unit 2.

The solenoid 3 has an elastic part 18 that pushes the mover 8 away from the stator 7 (in the direction of arrow X1 in Figure 1). The elastic part 18 is, for example, a spring (conical spring). One end of the elastic part 18 abuts against the first magnetic frame 10, and the other end abuts against a protrusion 19 at the tip of the mover 8.

(Overview of valve section 2)
As shown in Figure 1, the valve unit 2 includes a body 22 that constitutes part of the housing 4 of the proportional valve 1. The body 22 is made of, for example, a non-magnetic material. The body 22 is formed, for example, in a cylindrical shape with a hole 23 penetrating in the axial direction of the body 22 (the X-axis direction in Figure 1). A valve 24, the valve opening of which is set by the solenoid 3, and a plug 25 into which the valve 24 is inserted are inserted into the hole 23. The end of the body 22, into which the valve 24 is inserted, is sealed by the plug 25.

A seal 20 is provided between the second magnetic frame 11 and the body 22 to seal the gap between them. The seal 20 is, for example, an O-ring. The body 22 has an air supply port 26 that supplies fluid into the proportional valve 1 and an output port 27 that outputs fluid from the proportional valve 1.

The valve 24 is, for example, a poppet valve that moves perpendicularly from the valve seat 28 (in the X-axis direction in Figure 1). The poppet-type valve 24 moves linearly in the perpendicular direction when driven by the solenoid 3. In this example, the valve seat 28 is, for example, the tip portion of the plug 25. In this example, the valve 24 has an opening/closing portion 29 for opening and closing the valve seat 28. The opening/closing portion 29 is formed circumferentially around the outer periphery of the valve 24.

The valve 24 has a valve stem 31, which forms the main body of the valve 24. The valve stem 31 has the aforementioned opening/closing portion 29 on its outer surface. The opening/closing portion 29 has a seat 32 formed near the axial center of the valve stem 31, and a valve element 33 attached to this seat 32. The valve element 33 is provided in an annular shape along the circumferential direction of the valve stem 31. The valve stem 31 has a sliding portion 34 that is slidable within the plug 25. The sliding portion 34 is formed in a shape that is formed around the entire circumferential direction on the outer surface of the valve stem 31, i.e., in a flange shape.

The plug 25 has, for example, a hole 35 for inserting the valve 24 and a hole 37 for attaching a manual operating shaft 36 for manually operating the valve 24. The diameter of the hole 35 is larger than the diameter of the hole 37. One end of the valve stem 31 of the valve 24 is supported on a stepped support portion 38 provided on the body 22 at the boundary with the solenoid 3, and the other end of the valve stem 31 is supported on the inner surface of the hole 35 in the plug 25.

As shown in FIG. 2, a recess 41 that is lowered a predetermined amount relative to the outer peripheral surface of the plug 25 is formed around the circumferential direction of the plug 25 at a position near the tip. In this example, the plug 25 has a tip end 42 and a base end 43, sandwiched between the recess 41. The tip end 42 is, for example, a portion closer to the solenoid 3 than the recess 41. The base end 43 is, for example, a portion farther from the solenoid 3 than the recess 41. The valve seat 28 is, for example, formed by the tip (tip end 42) of the plug 25. The valve seat 28 is formed in an annular shape along the opening of the hole 35 of the plug 25.

The plug 25 has a hole 44 that connects the internal bore 35 to the air supply port 26. The hole 44 is formed, for example, in the recess 41 of the plug 25. Multiple holes 44 are provided at equal intervals around the circumference of the plug 25. The plug 25 is attached to the body 22 by threading a threaded portion 45 (e.g., a male thread) provided at the base end into a threaded portion 46 (e.g., a female thread) formed on the inner surface of the body 22.

As shown in FIG. 1, the proportional valve 1 has a valve chamber 49 whose outlet is opened and closed by the valve 24. In this example, the valve chamber 49 is an area inside the plug 25 that is surrounded by the inner surface of the plug 25, the valve stem 31, and the inner surface of the body 22. The valve chamber 49 is in communication with the air supply port 26 to take in fluid. That is, fluid flows from the air supply port 26 into the valve chamber 49. The valve 24 is in an open state when it moves away from the valve seat 28, and in a closed state when it contacts the valve seat 28.

A seal 50 for sealing the valve chamber 49 is provided between the inner surface of the body 22 and the plug 25. In this example, the seal 50 includes a first seal 50a provided between the tip end 42 of the plug 25 and the inner surface of the body 22, and a second seal 50b provided between the base end 43 of the plug 25 and the inner surface of the body 22. The first seal 50a and the second seal 50b are, for example, O-rings.

The sliding portion 34 has a seal portion 51 for sealing the valve chamber 49. The seal portion 51 is, for example, an O-ring. The seal portion 51 slides along the inner surface of the hole 35 in the plug 25 when the valve 24 moves linearly within the hole 35 in the body 22.

(Opening and closing operation of proportional valve 1)
1, when the coil 6 is excited, the mover 8 is attracted by the coil 6, causing the mover 8 to move linearly in a direction approaching the stator 7 (the direction of arrow X2 in FIG. 1). Specifically, when the coil 6 is excited, the mover 8 moves linearly in a direction approaching the stator 7 against the elastic portion 18, causing the valve 24 to move away from the valve seat 28. The mover 8 is then placed at a position corresponding to the current i flowing through the coil 6, and the valve 24 opens to a degree corresponding to the position of the mover 8.

As shown in Figure 3, when the coil 6 is de-energized, the elastic force of the elastic portion 18 causes the mover 8 to move linearly away from the stator 7 (in the direction of arrow X1 in Figure 3). This causes the valve 24 to come into contact with the valve seat 28, closing the valve 24.

(Overview of manual operation shaft 36)
1, the manual operating shaft 36 has a flange portion 53 that engages with the side surface of the hole 35, and a shaft body 54 that is formed with a smaller diameter than the flange portion 53. A seal portion 55 that seals the gap between the manual operating shaft 36 and the hole 37 is attached to the periphery of the shaft body 54. When the manual operating shaft 36 is pressed, it moves the valve 24 linearly in the opening direction. This allows the valve 24 to be manually switched to an open state.

(Balanced type explanation)
1 , the pressure of the fluid in the valve chamber 49 acts on the opening/closing portion 29 of the valve 24 and the sliding portion 34 of the valve 24. In the case of a balanced proportional valve 1, the area of the valve 24 that receives the fluid pressure at the opening/closing portion 29 is the same as the area of the valve 24 that receives the fluid pressure at the sliding portion 34. Therefore, the pressure received by the opening/closing portion 29 and the pressure received by the sliding portion 34 cancel each other out. Therefore, no pressure difference occurs between the movable element 8 and the valve 24.

Figure 4 shows a graph illustrating the relationship between the current i applied to the solenoid 3 and the flow rate Q through the proportional valve 1. Note that Figure 4 illustrates an example of four pressures P1 to P4 (P1<P2<P3<P4). In the case of a balanced proportional valve 1, when current i flows through the solenoid 3, the timing at which the valve opens is consistent regardless of the fluid pressure. In other words, the change in the characteristic between the flow rate Q and the current i takes a waveform that ensures that the timing at which the valve opens is consistent. In this way, with a balanced type, there is no need for waveform changes that would cause the timing at which the valve opens to change depending on the fluid pressure. Note that the change in the characteristic between the flow rate Q and the current i takes a waveform with a steeper slope as the pressure increases.

Figure 5 shows a graph illustrating the relationship between the current i applied to the solenoid 3 and the effective cross-sectional area S of the flow path. The effective cross-sectional area S is an index that indicates, for example, the opening degree of the valve 24. In the case of a balanced proportional valve 1, the change characteristic between the effective cross-sectional area S and the current i has the same waveform regardless of the fluid pressure. In other words, the change characteristic between the effective cross-sectional area S and the current i does not have to have different waveforms depending on the pressure. Note that the effective cross-sectional area S changes more significantly as the current i increases.

(Overview of Proportional Valve Controller 58)
1 , the proportional valve 1 includes a circuit board 59 of a proportional valve control device 58. The circuit board 59 is covered by a case 60 that forms part of the housing 4 of the proportional valve 1. The circuit board 59 is electrically connected to the coil 6 of the solenoid 3. The proportional valve 1 includes a connector 61 at an end of the case 60 for electrically connecting to an external device (not shown). A terminal 62 extending from the circuit board 59 is arranged inside the connector 61.

As shown in FIG. 6 , the proportional valve control device 58 includes a computing device 64 that controls the operation of the proportional valve 1. The computing device 64 is, for example, an MPU (Micro Processor Unit). The computing device 64 has a power supply port 66 to which a power supply line 65 is connected, an input line port 68 to which an input line 67 is connected, and a GND port 70 to which a GND line 69 is connected. The power supply line 65 supplies, for example, the power required for operation to the computing device 64. The input signal input to the input line 67 includes, for example, a set value Q' for the flow rate Q to be output from the proportional valve 1.

The proportional valve control device 58 has a power supply circuit 71 that steps down the voltage input from the power supply line 65 to a drive voltage for the arithmetic unit 64. The output of the power supply circuit 71 is connected to the power supply port 66.
The proportional valve control device 58 has a voltage dividing resistor 72 that divides the voltage of the input signal input to the input line 67. The voltage dividing resistor 72 has two resistors R1 and R2. The midpoint of the resistors R1 and R2 is connected to an input line port 68. The input signal input from the input line 67 is input to the arithmetic unit 64 at the input line port 68. Note that since the input signal is an analog signal, the input line port 68 is an A/D conversion port.

(General Description of Pressure Sensor 74)
6 and 7, the proportional valve control device 58 is connected to a pressure sensor 74 that detects the pressure of the fluid. In this example, the pressure sensor 74 includes, for example, a first pressure sensor 74a that detects the pressure of the fluid (primary fluid) flowing through the air supply port 26, and a second pressure sensor 74b that detects the pressure of the fluid (secondary fluid) flowing through the output port 27. As shown in FIG. 7, the first pressure sensor 74a is connected to the port of the air supply port 26. The second pressure sensor 74b is connected to the port of the output port 27.

As shown in FIG. 6, the calculation device 64 has a first pressure input port 75a that inputs pressure information Sp (first pressure information Sp1) from the first pressure sensor 74a, and a second pressure input port 75b that inputs pressure information Sp (second pressure information Sp2) from the second pressure sensor 74b. The first pressure input port 75a inputs the first pressure information Sp1 from the first pressure sensor 74a via wiring 76a. The second pressure input port 75b inputs the second pressure information Sp2 from the second pressure sensor 74b via wiring 76b. The pressure information Sp is an analog signal. Therefore, the first pressure input port 75a and the second pressure input port 75b are A/D conversion ports.

(Overview of the Current Control Circuit 77)
The proportional valve 1 includes a current control circuit 77 that controls the current flowing through the solenoid 3. The input of the current control circuit 77 is connected to a control port 79 of the arithmetic unit 64 via a wire 78. The arithmetic unit 64 outputs a control signal I for determining the current i to be flowed through the solenoid 3 from the control port 79 to the current control circuit 77, thereby switching the current i to be flowed through the solenoid 3, i.e., the opening degree of the valve 24. The control signal I is an analog signal. Therefore, the control port 79 is a D/A conversion port.

The current control circuit 77 includes a feedback operational amplifier 81 and a switching element 82 that switches the current path of the solenoid 3 on and off. The operational amplifier 81 has a positive input terminal connected to the control port 79 via a voltage-dividing resistor 83, and a negative input terminal connected to the switching element 82. The output terminal of the operational amplifier 81 is connected to the switching element 82 via a diode 84 and resistor R3.

The switching element 82 is, for example, an npn-type transistor. In this example, the collector terminal of the transistor is connected to the coil 6, and the emitter terminal is connected to GND via resistor R5. The base terminal of the transistor is connected to the midpoint of resistors R3 and R4. A Zener diode 85 is connected between the collector terminal and base terminal of the transistor to keep the voltage applied to the transistor constant.

The operational amplifier 81 controls the on/off of the switching element 82 by outputting the difference between the + input terminal and the - input terminal from the output terminal. Specifically, the operational amplifier 81 controls the current i flowing through the coil 6 of the solenoid 3 by turning on the switching element 82 while the signal at the + input terminal is equal to or greater than the signal at the - input terminal. In this way, a constant value of current i corresponding to the control signal I flows through the coil 6.

(Overview of Temperature Sensor 86)
The proportional valve 1 includes a temperature sensor 86 that detects the temperature of the fluid. The temperature sensor 86 detects, for example, the temperature of the fluid flowing through the output port 27. The temperature sensor 86 outputs the detected temperature information St to a temperature input port 87 of the calculation device 64. The temperature information St is, for example, an analog signal. Therefore, the temperature input port 87 is an A/D conversion port.

The temperature sensor 86 is, for example, a thermistor 88. The thermistor 88 has, for example, a pair of resistors R6 and R7. The thermistor 88 has resistor R6 connected to a power supply and resistor R7 connected to GND. The midpoint of resistors R6 and R7 of the thermistor 88 is connected to a temperature input port 87 of the computing device 64. The thermistor 88 outputs the voltage at the midpoint of resistors R6 and R7 to the temperature input port 87 as temperature information St.

The proportional valve control device 58 is equipped with an output line 89 for outputting detection information Sk detected in the proportional valve 1 to the outside of the proportional valve 1. The output line 89 is connected to an output line port 90 provided in the calculation device 64. The detection information Sk is, for example, at least one of the aforementioned pressure information Sp and flow rate information Sq from a flow rate sensor 91 (see Figure 7) that detects the flow rate Q of the fluid. The flow rate sensor 91 detects, for example, the flow rate Q flowing out to the output port 27.

(Calculation of control signal I)
6 , the proportional valve control device 58 includes a set value acquisition unit 94 that acquires a set value Q' of the fluid output from the output port 27 of the proportional valve 1. The set value acquisition unit 94 is provided in, for example, the arithmetic unit 64. The set value Q' is, for example, the value of the flow rate Q that the operator wants to output from the proportional valve 1. The set value acquisition unit 94 acquires the set value Q' input to the arithmetic unit 64 via the input line 67.

The proportional valve control device 58 includes a control unit 95 that controls the opening and closing of the valve unit 2. The control unit 95 is provided, for example, in the calculation device 64. The control unit 95 outputs a control signal I corresponding to the set value Q' to the current control circuit 77 to control the solenoid 3, thereby adjusting the valve opening of the valve unit 2.

The proportional valve control device 58 is equipped with a pressure information input unit 96 that inputs pressure information Sp from the pressure sensor 74. The pressure information input unit 96 is provided, for example, in the calculation device 64. In this example, the pressure information input unit 96 inputs pressure information Sp from at least one of the first pressure sensor 74a and the second pressure sensor 74b (in this example, both). The pressure information input unit 96 inputs pressure information Sp from the first pressure input port 75a and the second pressure input port 75b.

The proportional valve control device 58 includes a temperature information input unit 97 that inputs temperature information St from the temperature sensor 86. The temperature information input unit 97 is provided, for example, in the calculation device 64. The temperature information input unit 97 inputs the temperature information St from the temperature input port 87.

When setting the control signal I according to the set value Q' of the fluid flow rate Q, the control unit 95 uses the pressure information Sp and temperature information St to determine the control signal I. Specifically, when the operator inputs the desired flow rate Q, the calculation device 64 takes in this flow rate Q as the set value Q'. The control unit 95 then adjusts the valve opening of the valve unit 2 by controlling the current i flowing through the solenoid 3 so that the proportional valve 1 outputs a fluid that corresponds to the set value Q'.

(Operation of the first embodiment)
Next, the operation of the proportional valve control device 58 (proportional valve control method) of this embodiment will be described.
8, in step 101, the arithmetic device 64 inputs the set value Q′ of the flow rate Q input by the operator. In this example, the arithmetic device 64 acquires the set value Q′ using the set value acquisition unit 94.

In step 102, the control unit 95 detects pressure information Sp from the pressure sensor 74 and temperature information St from the temperature sensor 86. In this example, the control unit 95 inputs the pressure information Sp via the pressure information input unit 96 and the temperature information St via the temperature information input unit 97.

In step 103, the control unit 95 executes flow rate control so that the fluid is output from the proportional valve 1 at a flow rate Q set by the operator.
In step 104, the control unit 95 uses the input pressure information Sp and temperature information St to calculate a control signal I. In this example, the control unit 95 finds the effective cross-sectional area S corresponding to the set value Q' by substituting the set value Q', the pressure information Sp, and the temperature information St into a flow rate calculation formula that represents the relationship between the effective cross-sectional area S of the valve unit 2 and the set value Q'.

For example, two flow rate calculation formulas are provided: one to be used when the fluid is in choked flow, and one to be used when the fluid is in subsonic flow. Whether the fluid is in choked flow or subsonic flow is determined, for example, using the first pressure information Sp1 and the second pressure information Sp2. When the fluid is in choked flow, the effective cross-sectional area S is calculated by substituting the set value Q', pressure information Sp, and temperature information St into the flow rate calculation formula used for choked flow. When the fluid is in subsonic flow, the effective cross-sectional area S is calculated by substituting the set value Q', pressure information Sp, and temperature information St into the flow rate calculation formula used for subsonic flow.

After calculating the effective cross-sectional area S, the control unit 95 calculates the control signal I using the formula "I = S/M." In this formula, "M" is a correction coefficient calculated from the product performance of the proportional valve 1. In this way, after calculating the effective cross-sectional area S, the control unit 95 calculates the control signal I using the calculated effective cross-sectional area S and the correction coefficient M for adjusting the valve opening.

In step 105, the calculation device 64 outputs the calculated control signal I to the current control circuit 77. The current control circuit 77 sets the valve opening degree according to the control signal I by passing a current i according to the control signal I through the solenoid 3. In this way, the valve 24 is adjusted to a valve opening degree according to the pressure (including temperature) of the fluid.

In step 106, the calculation device 64 detects the pressure information Sp and temperature information St after adjusting the opening of the valve 24. That is, the calculation device 64 reacquires the current pressure and temperature in preparation for the next time a new control signal I is calculated.

In step 107, the calculation device 64 determines whether or not control should be released. Release of control means, for example, releasing (terminating) the process of determining a control signal I from the pressure information Sp and temperature information St and sending it to the current control circuit 77, i.e., the flow control. A command to release control is preferably input to the calculation device 64 via the input line 67, for example.

If control is not released in step 107, the process returns to step 103 and the series of processes for calculating the control signal I are executed again. That is, the control unit 95 repeatedly executes the process of acquiring pressure information Sp and temperature information St and calculating the control signal I. On the other hand, if control is released in 107, the process ends.

(Effects of the first embodiment)
According to the proportional valve control device 58 (proportional valve control method) of the above embodiment, the following effects can be obtained.

(1-1) The proportional valve 1 is a balanced type in which the valve opening of the valve element 2 is set by the suction force of the solenoid 3 and the elastic force of the elastic element 18 attached to the solenoid 3, and the pressures acting on the valve element 2 and the solenoid 3 are equal. The proportional valve control device 58, which controls the balanced proportional valve 1, includes a set value acquisition unit 94, a control unit 95, a pressure information input unit 96, and a temperature information input unit 97. The set value acquisition unit 94 acquires a set value Q' of the fluid discharged from the output port 27. The control unit 95 outputs a control signal I corresponding to the set value Q' to the current control circuit 77 to control the solenoid 3, thereby adjusting the valve opening of the valve element 2. The pressure information input unit 96 inputs pressure information Sp from at least one of the first pressure sensor 74a, which detects the pressure of the fluid flowing through the air supply port 26, and the second pressure sensor 74b, which detects the pressure of the fluid flowing through the output port 27. The temperature information input unit 97 inputs temperature information St from the temperature sensor 86 that detects the temperature of the fluid at the output port 27. When setting the control signal I according to the set value Q' of the fluid flow rate Q, the control unit 95 obtains the control signal I using the pressure information Sp and the temperature information St.

With this configuration, even if the pressure or temperature of the fluid changes, a control signal I corresponding to the pressure or temperature is obtained and the current control circuit 77 is controlled. This makes the flow rate Q less susceptible to changes in pressure or temperature. In this way, it is possible to control the flow rate Q to a desired value without using a complex method such as directly detecting the output of the flow rate Q and controlling the flow rate Q. This makes it easy to adjust the flow rate Q.

(1-2) The control unit 95 repeatedly executes the process of acquiring pressure information Sp and temperature information St and calculating the control signal I. This configuration enables optimization of the control signal I, making it less likely that deviations will occur in the output of the flow rate Q.

(1-3) The control unit 95 calculates the effective cross-sectional area S corresponding to the set value Q' by substituting the set value Q', pressure information Sp, and temperature information St into a flow rate calculation formula that represents the relationship between the effective cross-sectional area S of the valve unit 2 and the set value Q', and calculates the control signal I using the effective cross-sectional area S and a correction coefficient M for adjusting the valve opening. With this configuration, the optimal control signal I can be easily calculated by calculations using the flow rate calculation formula and the correction coefficient M.

(1-4) The proportional valve control device 58 is equipped with an output line 89 for outputting the detection information Sk detected by the proportional valve 1 to an external device. This configuration allows the detection information Sk detected by the proportional valve 1 to be provided to external equipment.

(1-5) The detection information Sk is at least one of pressure information Sp and flow rate information Sq from the flow sensor 91 that detects the fluid flow rate Q. With this configuration, at least one of the fluid pressure and flow rate Q detected by the proportional valve 1 can be provided to an external device.

(1-6) Because the proportional valve 1 is a balanced type, the current i applied to the solenoid 3 and the effective cross-sectional area S, which indicates the opening degree of the valve 24, are less affected by the fluid pressure. This makes it possible to minimize the performance difference (so-called response differential) caused by losses in the series of operations from when the valve 24 begins to open to when it is fully open and then when it closes again. This makes it easier to control the opening and closing of the valve 24.

Second Embodiment
Next, a second embodiment will be described. The second embodiment is an example in which pressure control can be performed in addition to the flow rate control of the first embodiment. Therefore, the same parts as those in the first embodiment are denoted by the same reference numerals and their description will be omitted, and only the differences will be described in detail.

(Overview of Proportional Valve Controller 58)
9 , the proportional valve control device 58 includes a mode switching unit 99 that switches the operation mode of the control unit 95. The mode switching unit 99 switches the operation mode of the control unit 95 between a first mode in which the flow rate Q of the fluid is controlled based on pressure information Sp and temperature information St, and a second mode in which the pressure of the fluid is controlled based on the pressure information Sp. The first mode is the flow rate control mode described in the first embodiment. The second mode is a pressure control mode in which the pressure of the fluid is adjusted.

The mode switching unit 99 is, for example, a switch provided in the circuit of the proportional valve control device 58. Therefore, the calculation device 64 sets the operating mode of the control unit 95 to either the first mode or the second mode based on the switch signal of the mode switching unit 99. Therefore, if the mode switching unit 99 is operated to select flow rate control, the calculation device 64 performs flow rate control. Also, if the mode switching unit 99 is operated to select pressure control, the calculation device 64 performs pressure control.

(Operation of the second embodiment)
Next, the operation of the proportional valve control device 58 (proportional valve control method) of this embodiment will be described. In the first mode (flow rate control mode), the processing described in the first embodiment is executed. Therefore, here, the second mode (pressure control mode) will be described in detail.

As shown in FIG. 10, in step 201, the calculation device 64 inputs the pressure setting value P' input by the operator. In this example, the calculation device 64 acquires the setting value P' using the setting value acquisition unit 94.

In step 202, if the control unit 95 receives a switch signal from the mode switching unit 99 selecting pressure control, it performs pressure adjustment as pressure control. Pressure adjustment is, for example, a process for adjusting the pressure of the current fluid (fluid at the output port 27) to the set value P'.

In step 203, the control unit 95 opens the proportional valve 1. That is, the control unit 95 outputs a control signal I based on the set value P' to the current control circuit 77, thereby opening the proportional valve 1.

In step 204, the control unit 95 detects pressure information Sp from the pressure sensor 74. In this example, the pressure information input unit 96 of the calculation device 64 inputs the pressure information Sp.
In step 205, the control unit 95 determines whether the current pressure is the set value P'. If the current pressure is the set value P', the process proceeds to step 206. On the other hand, if the current pressure is not the set value P', the process returns to step 202 and the processes of steps 202 to 204 described above are executed again.

In step 206, when the pressure reaches the set value P', the control unit 95 performs pressure monitoring as pressure control. Pressure monitoring is a process of monitoring whether the current pressure is being maintained at the set value P'.

In step 207, the control unit 95 detects pressure information Sp from the pressure sensor 74. In this example, the pressure information input unit 96 of the arithmetic unit 64 inputs the pressure information Sp.
In step 208, the control unit 95 determines whether the current pressure is the set value P'. If the current pressure is the set value P', the process proceeds to step 209. On the other hand, if the current pressure is not the set value P', the process returns to step 202, and the processes of steps 202 to 207 described above are executed again.

In step 209, the calculation device 64 determines whether or not control should be released. Release of control means, for example, releasing (terminating) the second mode (pressure control mode). The command to release control is preferably input to the calculation device 64 via, for example, input line 67.

If the control is not released in step 209, the process returns to step 206 and continues the second mode. On the other hand, if the control is released in 209, the process ends.
(Effects of the second embodiment)
According to the proportional valve control device 58 (proportional valve control method) of the above embodiment, the following effects can be obtained.

(2-1) The proportional valve control device 58 includes a mode switching unit 99 that switches the operating mode of the control unit 95. The mode switching unit 99 switches the operating mode of the control unit 95 between a first mode in which the flow rate Q of the fluid is controlled based on pressure information Sp and temperature information St, and a second mode in which the pressure of the fluid is controlled based on pressure information Sp.

This configuration allows the operating mode of the control unit 95 to be switched between the first mode and the second mode as needed. Furthermore, the pressure sensor 74 can be used for both flow rate control and pressure control. This allows for effective use of the pressure sensor 74. Furthermore, if the pressure sensor 74 is already present in the proportional valve 1, flow rate control and pressure control can be performed without the need to install a new sensor.

(Other embodiments)
This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

In each embodiment, the valve 24 is not limited to a poppet valve and may be, for example, a spool valve.
In each embodiment, the proportional valve 1 is not limited to a two-port type having, for example, the intake port 26 and the output port 27, but may be a three-port type having an exhaust port in addition to these.

In each embodiment, the pressure sensor 74 may be of various types, such as a piezoelectric element type, a capacitance type, or a gas type.
In each embodiment, the temperature sensor 86 may detect the temperature of the primary fluid instead of the secondary fluid.

- In each embodiment, the temperature sensor 86 is not limited to a thermistor 88, and may be, for example, a thermocouple or an IC temperature sensor. Furthermore, the temperature sensor 86 is not limited to a contact type, and may be a non-contact type.

In each embodiment, the flow rate calculation formula may be any formula that expresses the relationship between the desired flow rate Q, the effective cross-sectional area S of the proportional valve 1, and the temperature of the fluid.
In each embodiment, the output line 89 may be omitted.

- In the second embodiment, the mode switching unit 99 is not limited to a switch, and may be, for example, a functional block (software) that performs mode switching based on a signal for mode switching.

In each embodiment, the fluid supplied to the proportional valve 1 is not limited to a constant pressure, but may be at different pressures depending on the type of fluid used.
In each embodiment, the fluid may be either a gas or a liquid.

- In each embodiment, the proportional valve 1 can be applied to, for example, factory automation (FA) equipment and medical equipment. The proportional valve 1 may also be used in fluid control devices used in the food industry, heating devices for packaging chemicals, and gas control devices related to semiconductor manufacturing.

- In each embodiment, the set value acquisition unit 94, control unit 95, pressure information input unit 96, and temperature information input unit 97 may be configured as [1] one or more processors operating according to a computer program (software), or [2] a combination of such a processor and one or more dedicated hardware circuits, such as an application-specific integrated circuit (ASIC), that execute at least some of the various processes. The processor includes a CPU and memory, such as RAM and ROM, that stores program code or instructions configured to cause the CPU to execute the processes. The memory (computer-readable medium) includes any available medium that can be accessed by a general-purpose or dedicated computer. Alternatively, instead of a computer including the above processor, a processing circuit configured with one or more dedicated hardware circuits that execute all of the various processes may be used.

- In each embodiment, the set value acquisition unit 94, control unit 95, pressure information input unit 96, and temperature information input unit 97 may be configured from independent processors, or may be constructed from a processor with some of its functions shared. In this way, the set value acquisition unit 94, control unit 95, pressure information input unit 96, and temperature information input unit 97 are not limited to being independent functional blocks, but may be configured from a single functional block, or may be configured from a functional block with some functions shared.

- In each embodiment, the present disclosure has been described with reference to examples, but it is understood that the present disclosure is not limited to those examples or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

1...proportional valve, 2...valve section, 3...solenoid, 18...elastic section, 26...air supply port, 27...output port, 58...proportional valve control device, 74...pressure sensor, 74a...first pressure sensor, 74b...second pressure sensor, 77...current control circuit, 86...temperature sensor, 89...output line, 91...flow rate sensor, 94...set value acquisition section, 95...control section, 96...pressure information input section, 97...temperature information input section, 99...mode switching section, Q...flow rate, Q'...set value, P'...set value, I...control signal, Sp...pressure information, St...temperature information, Sk...detection information, Sq...flow rate information.

Claims (6)

A proportional valve control device for controlling a balanced proportional valve in which the valve opening degree of a valve portion is set by the attractive force of a solenoid and the elastic force of an elastic portion attached to the solenoid, and the pressure acting on the valve portion and the solenoid is the same,
a set value acquisition unit that acquires a set value of the fluid to be output from the output port;
a control unit that outputs a control signal corresponding to the set value to a current control circuit to control the solenoid, thereby adjusting the valve opening degree of the valve unit;
a pressure information input unit that inputs pressure information from at least one of a first pressure sensor that detects the pressure of the fluid flowing through an air supply port and a second pressure sensor that detects the pressure of the fluid flowing through the output port;
a temperature information input unit that inputs temperature information from a temperature sensor that detects the temperature of the fluid in either the air supply port or the output port,
when setting the control signal according to the set value of the flow rate of the fluid, the control unit calculates the control signal using the pressure information and the temperature information;
the valve portion includes a valve that is displaced in a valve opening direction in which the valve portion opens and in a valve closing direction that is opposite to the valve opening direction and in which the valve portion closes, when the solenoid is controlled; and a valve chamber that communicates with the air supply port regardless of the position of the valve,
the valve includes a first operating surface on which pressure from the fluid in the valve chamber acts in the valve-opening direction, and a second operating surface on which pressure from the fluid in the valve chamber acts in the valve-closing direction,
the control unit calculates the effective cross-sectional area corresponding to the set value by substituting the set value, the pressure information, and the temperature information into a flow rate calculation formula that represents the relationship between the effective cross-sectional area of the valve unit and the set value, and calculates the control signal using a correction coefficient for adjusting the valve opening and the effective cross-sectional area . The proportional valve control device according to claim 1 , wherein the control unit repeatedly executes a process of acquiring the pressure information and the temperature information and determining the control signal. The proportional valve control device according to claim 1, further comprising an output line for outputting detection information detected in the proportional valve to an outside of the proportional valve. 4. The proportional valve control device according to claim 3 , wherein the detection information is at least one of the pressure information and flow rate information of a flow rate sensor that detects the flow rate of the fluid. 2. The proportional valve control device according to claim 1, further comprising a mode switching unit that switches the operation mode of the control unit between a first mode in which the flow rate of the fluid is controlled based on the pressure information and the temperature information, and a second mode in which the pressure of the fluid is controlled based on the pressure information. A proportional valve control method for controlling a balanced proportional valve in which a valve opening degree of a valve portion is set by the attractive force of a solenoid and the elastic force of an elastic portion attached to the solenoid, and pressures acting on the valve portion and the solenoid are equal, comprising:
Obtaining a setpoint for fluid output from an output port;
inputting pressure information from at least one of a first pressure sensor that detects the pressure of the fluid flowing through an air supply port and a second pressure sensor that detects the pressure of the fluid flowing through the output port;
inputting temperature information from a temperature sensor that detects a temperature of the fluid in either the air supply port or the output port;
a proportional valve control device that controls the proportional valve, wherein the proportional valve control signal is output to a current control circuit to control the solenoid, thereby determining the control signal using the pressure information and the temperature information when adjusting the valve opening of the valve unit;
the valve portion includes a valve that is displaced in a valve opening direction in which the valve portion opens and in a valve closing direction that is opposite to the valve opening direction and in which the valve portion closes, when the solenoid is controlled; and a valve chamber that communicates with the air supply port regardless of the position of the valve,
the valve includes a first operating surface on which pressure from the fluid in the valve chamber acts in the valve-opening direction, and a second operating surface on which pressure from the fluid in the valve chamber acts in the valve-closing direction,
a proportional valve control method for determining the effective cross-sectional area corresponding to the set value by substituting the set value, the pressure information, and the temperature information into a flow rate calculation formula that expresses the relationship between the effective cross-sectional area of the valve portion and the set value, and determining the control signal using the effective cross-sectional area and a correction coefficient for adjusting the valve opening.